Neonatal Hypoglycemia

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Neonatal Hypoglycemia

• Amy Bloomquist, RNC,MSN

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Definition

• The S.T.A.B.L.E. Program defines hypoglycemia as
• Glucose delivery or availability is inadequate
  to meet glucose demand (Karlsen, 2006)

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What is Normal?

• Defining a normal glucose level remains
  controversial
• 50 110 mg/dl (Karlsen, 2006)
• gt 40 mg/dl (Verklan Walden, 2004)
• gt 30 term, gt 20 preterm (Kenner Lott, 2004)
• gt 45 mg/dl (Cowett, R. as cited by Barnes-Powell,
  2007)

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Incidence of Hypoglycemia

• Overall Incidence 1- 5/1000 live births
• Normal newborns 10 if feeding is delayed for
  3-6 hours after birth
• At-Risk Infants 30
• LGA 8
• Preterm 15
• SGA 15
• IDM 20

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Why is hypoglycemia a problem?

• Glucose is the primary fuel for the brain.
• The brain needs a steady supply of glucose to
  function normally.
• Glucose is the fetuss only source of
  carbohydrate.

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Why is hypoglycemia a problem?

• Compared with adults, infants have a higher
  brain to body weight ratio, resulting in higher
  glucose demand in relation to glucose production
  capacity.
• Cerebral glucose utilization accounts for 90 of
  the neonates glucose consumption.

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Preparation for Birth

• Fetal plasma glucose is 60 80 of the maternal
  glucose level.
• The fetus stores glucose in the form of glycogen
  (liver, heart, lung, and skeletal muscle).
• Most of the glycogen is made and stored in the
  last month of the 3rd trimester.

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Preparation for Birth

• The fetus has limited ability to convert glycogen
  to glucose and must rely upon placental transfer
  of glucose to meet energy needs.
• When the infant is born, the cord is cut and so
  is the major supply of glucose!

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Preparation for Birth

• The transition from fetus to newborn creates a
  significant energy drain on the newborn.
• The newborn is now required to meet increased
  metabolic demands while changing the energy
  source from a placenta-supplied source to an
  external food source.

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Infants at Highest Risk

• lt 37 weeks gestation
• Infant of a diabetic mother
• Small for gestational age
• Large for gestational age
• Stressed/ill infants
• Exposure to certain medications
• Treatment of preterm labor
• Treatment of hypertension
• Treatment of type 2 diabetes
• Benzothiazide diuretics
• Tricyclic antidepressants in the 3rd trimester

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Factors that negatively affect glucose
availability after birth

• Inadequate Glycogen
• Increased Utilization of Glucose
• Excessive Insulin

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Inadequate Glycogen

• Glycogen stores increase rapidly in the last
  month of the 3rd trimester
• Preterm infants are born before this occurs.
  What little glycogen is available is used up
  rapidly and their supply is depleted.

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Inadequate Glycogen

• SGA birth weight lt 10 percentile. Chronically
  stressed infants have higher metabolic demands
  and use up available glucose for growth and
  survival.
• Markedly post-mature infants are at increased
  risk due to increased metabolic demand.

14
Increased Utilization of Glucose

• Sick/Stressed infants
• Causes increase in metabolic demand
• Uses up glucose quickly.
• These include all sick, premature and SGA infants.

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Excessive Insulin - IDM

• Infants of Diabetic Mothers
• Many consequences for the neonate
• Single most important factor in determining the
  outcome for the infant is maternal glucose
  control

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IDM Risks gt general population

• Birth injury is doubled
• C/S is tripled
• NICU admission is quadrupled
• Stillbirth is x 5 greater
• Congenital anomalies are x 2 5 greater

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IDM - Incidence

• 106,000 in 1999
• Rate of Type II Diabetes has increased by 33 in
  past 20 years
• Women at highest risk
• African-American
• Hispanic
• American Indian
• Asian
• Obese

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IDM Effects on Fetus

• Glucose crosses the placenta
• Insulin does not cross the placenta
• Results fetus produces own insulin in the
  presence of elevated glucose from the mother
• Excessive formation of oxygen radicals that
  damage the mitochondria
• This increase in oxidative stress results
  disrupts vascularization of the developing
  tissues.

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IDM fetal anomalies

• Hyperglycemia alters the expression of regulating
  genes leading to altered cellular mitosis and the
  normal timing of cell death. Excessive cell
  death results in fetal anomalies.
• Caudal regression syndrome
• Hydronephrosis
• Renal agenesis
• Micropenis
• Cystic kidneys
• Intestinal atresias

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Effect on CNS

• Anencephaly
• Spina bifida
• Caudal dysplasia
• CNS damage as a result of
• Birth trauma (macrosomia)
• Glucose and electrolyte abnormalities
• Perinatal asphyxia

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Other Effects on the Neonate

• RDS
• CHD
• VSD
• Asymmetric septal hypertrophy
• Thickened myocardium
• Transposition of the greater vessels
• Polycythemia and vascular sludging

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Nursing Management

• Complete evaluation and review of systems
• Early breast or bottle feeding within 30 minutes
• Glucose monitoring within 1 hour
• Monitor pre-feeding levels thereafter

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Monitoring

• Serum glucose level is the gold standard
• Bedside glucose levels are for screening

• Monitor at least hourly until glucose level has
  stabilized
• Know your hospital policy for monitoring infants
  at risk for hypoglycemia

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Signs Symptoms of Hypoglycemia

• Jitteriness
• Irritability
• Hypotonia
• Lethargy
• High-pitched cry
• Hypothermia

• Poor suck
• Tachypnea
• Cyanosis
• Apnea
• Seizures
• Cardiac arrest

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Treatment

• Oral feedings as tolerated
• If glucose is very low or the infant is not able
  to feed orally
• 2ml/kg of D10W IV bolus
• Follow up screenings within 30 minutes
• Repeat bolus if glucose is lt 50 mg/dl
• If unable to stabilize glucose consider
  increasing IV rate or glucose concentration

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Prevention

• Increase awareness of conditions that predispose
  an infant to hypoglycemia
• Early screening of at-risk infants
• Early and frequent feedings
• Maintain temperature

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References

• Barnes-Powell, L. (2007). Infants of Diabetic
  Mothers The effects of hyperglycemia on the
  fetus and neonate. Neonatal Network, 26(5) p.
  283-289.
• Karlsen, K. (2006) The S.T.A.B.L.E. Program.
  Pre-transport/Post-resuscitation Stabilization
  Care of /sick Infants, Guidelines for Neonatal
  Healthcare Providers. 5th Edition.
• Kenner, C., Lott, J. (2004). Neonatal Nursing
  Handbook. Elsevier.
• Verklan, M., Walden, M. (2004). Core
  Curriculum for Neonatal Intensive Care Nurses.
  Elsevier.